VERTEX 3701-2501 0-1/2 Inch MT4 Integrated Keyless Drill Chuck Clamping Capacity 0~1/2"; Shank MT4 Maximum T.I.R. does not exceed .002"; Keyless, self tightening design Integrated design maximizes rigidity & accuracy Integral Shank is more compact than a combined drill chuck and Arbor and eliminates the chuck slipping on its arbor